Integrated circuits generally comprise electrical traces electrically coupled to electronic devices, such as transistors, capacitors, resistors, and the like. As the size of the integrated circuits decrease, the electrical components, including the electrical traces and the electronic devices, become closer to each other. As is known in the art, a phenomenon referred to as crosstalk may occur wherein a signal transmitted on one line may create an undesired effect on another. This problem becomes increasingly troublesome as circuits shrink and the density of the circuits increase.
One attempt at reducing the effect of crosstalk is to shield the affected traces. In this attempt, critical signals such as clock signals are surrounded or shielded by metal traces and vias that are electrically coupled to ground. In this manner, the shielding tied to ground acts to prevent other electrical signals from reaching or affecting the clock signals. This method, however, requires a significant amount of area to implement and, thus, may require a larger die to implement a given circuit.
In another attempt, a twisted pair for differential signals or for single-ended signal and a reference signal, is created through multiple metal layers. In this attempt, however, the twisted pair has limited tunability in terms of characteristic impedance. Furthermore, the material in the core of the twists is not easily changed and devices cannot be placed in the core to further influence the characteristics of the signal. This attempt also requires additional die space and several metal layers due to the 3D geometry.
Therefore, there is a need for a system and method for preventing or reducing crosstalk that requires less die space.